Catheter

Abstract

The objective is to provide an asymmetrically bendable catheter configured such that a bent shape is different depending on whether the catheter distal part bends to one side or the other side. Disclosed is a catheter having a shaft, a first wire, a second wire, a leaf spring disposed in the lumen of the shaft so as to separate the lumen of the shaft into a first part where the first wire is disposed and a second part where the second wire is disposed, a supporting member, and a first coil having a lumen in which the first wire is disposed; the first coil fixed to a proximal end side of the leaf spring at two or more locations, and the first coil having a total length L 1 in its natural state and a total length L C1 at maximum compression, and a ratio L C1 /L 1 is 0.9 or more.

1 . A catheter, comprising:
 a shaft having a distal end, a proximal end, and a lumen extending in a longitudinal direction;   a first wire having a distal end and a proximal end and extending in the lumen of the shaft, the distal end being fixed to a distal end part of the shaft, and the proximal end being disposed at a proximal end part of the shaft;   a second wire having a distal end and a proximal end and extending in the lumen of the shaft, the distal end being fixed to a distal end part of the shaft, and the proximal end being disposed at a proximal end part of the shaft;   a leaf spring disposed in the lumen of the shaft so as to separate the lumen of the shaft into a first part where the first wire is disposed and a second part where the second wire is disposed in the longitudinal direction;   a supporting member, to which the proximal end of the leaf spring is fixed, extending in the longitudinal direction, having a lumen in which the first wire and the second wire are disposed, and being disposed proximal to the leaf spring; and   a first coil having a lumen in which the first wire is disposed and being disposed in the first part and distal to a distal end of the supporting member, wherein   the first coil is fixed to a proximal end side of the leaf spring at two or more locations, which include a first fixed portion and a second fixed portion so that the first coil has at least one unfixed portion including an intermediate unfixed portion, which is not fixed to the leaf spring and is located between the first fixed portion and the second fixed portion,   the second fixed portion is located proximal to the first fixed portion, and   the first coil has a total length L 1  in its natural state and a total length L C1  at maximum compression, and a ratio L C1 /L 1  is 0.9 or more.   
     
     
         2 . The catheter according to  claim 1 , wherein the supporting member is a tubular member. 
     
     
         3 . The catheter according to  claim 1 , wherein the first coil is a closely wound coil. 
     
     
         4 . The catheter according to  claim 1 , wherein an outer surface of the first coil is fixed to a surface of the leaf spring at the first fixed portion and the second fixed portion, the surface of the leaf spring defining a part of the first part of the lumen of the shaft. 
     
     
         5 . The catheter according to  claim 1 , wherein an unfixed portion having a longest length in the longitudinal direction among the at least one unfixed portion has a length in its natural state in the longitudinal direction of 50% or longer of the total length L 1  of the first coil in its natural state. 
     
     
         6 . The catheter according to  claim 1 , wherein the first coil is disposed in the first part of the lumen of the shaft so that the first coil has a distal unfixed portion, which does not include a fixed portion where the first coil and the leaf spring is fixed, between a distal end of the first coil and the first fixed portion. 
     
     
         7 . The catheter according to  claim 1 , further comprising a second coil having a lumen in which the first wire is disposed and being disposed in the first part and distal to the first coil. 
     
     
         8 . The catheter according to  claim 7 , wherein the second coil has a total length L 2  in its natural state and a total length L C2  at maximum compression, and the ratio L C2 /L 2  is less than 0.9. 
     
     
         9 . The catheter according to  claim 7 , wherein a bending stiffness of the first coil is greater than a bending stiffness of the second coil, and the difference between the bending stiffness of the first coil and the bending stiffness of the second coil is 50% or less. 
     
     
         10 . The catheter according to  claim 7 , wherein
 the first coil is formed of a helically wound first coil wire,   the second coil is formed of a helically wound second coil wire, and   a pitch interval of the first coil is shorter than a pitch interval of the second coil.   
     
     
         11 . The catheter according to  claim 10 , wherein a coil wire diameter of the first coil is the same as a coil wire diameter of the second coil, and a coil diameter of the first coil is the same as a coil diameter of the second coil. 
     
     
         12 . The catheter according to  claim 1 , further comprising a third coil having a lumen, wherein the third coil is disposed in the second part of the lumen of the shaft and the second wire is disposed in the lumen of the third coil. 
     
     
         13 . The catheter according to  claim 12 , wherein the third coil has a total length L 3  in its natural state and a total length L C3  at maximum compression, and the ratio L C3 /L 3  is less than 0.9. 
     
     
         14 . The catheter according to  claim 1 , further comprising:
 a second coil having a lumen,   a third coil having a lumen, and   a protection tube having a lumen, wherein the second coil is disposed in the first part of the lumen of the shaft, and the first wire is disposed in the lumen of the first coil and the lumen of the second coil so that the second coil is located at a distal side of the first coil,   the third coil is disposed in the second part of the lumen of the shaft, and the second wire is disposed in the lumen of the third coil, and   the protection tube is disposed in the lumen of the shaft so that the leaf spring, the first coil, the second coil, and the third coil are placed in the lumen of the protection tube.   
     
     
         15 . The catheter according to  claim 1 , wherein the first coil is fixed to the leaf spring by welding, soldering, bonding, or crimping at the first fixed part and the second fixed part. 
     
     
         16 . The catheter according to  claim 1 , wherein the intermediate unfixed portion has a length in its natural state in the longitudinal direction of 50% or longer of the total length L 1  of the first coil in its natural state.